1. Field of the Invention
The present invention relates to a method for adjusting a steering system and an adjustment apparatus for a steering system.
2. Description of Related Art
A rack-and-pinion steering system has been known as described in, for example, Japanese Patent Application Publication No. 2008-018828 (JP 2008-018828 A). The steering system has a pinion shaft that rotates in conjunction with a steering wheel, a rack shaft that meshes with the pinion shaft, and a housing that houses both the pinion shaft and the rack shaft. The rack shaft moves in an axial direction thereof in conjunction with rotation of the pinion shaft to allow the direction of wheels to be changed.
The steering system includes a support mechanism for eliminating backlash between the rack shaft and the pinion shaft. The support mechanism has a support yoke provided in a holding hole of the housing so as to be able to move back and forth, a yoke plug screw-threaded into the holding hole, and a compression coil spring interposed between the yoke plug and the support yoke. The support yoke is constantly biased toward the rack shaft by an elastic force of the compression coil spring. The support yoke supports the rack shaft so that the rack shaft is slidable along the axial direction thereof while pressing the rack shaft toward a pinion.
To suppress hammering sound resulting from abutting contact between the support yoke and the yoke plug, a predetermined amount of clearance is provided between the support yoke and the yoke plug. For strict management, the clearance is adjusted, for example, as follows. First, the yoke plug is temporarily fastened to the holding hole to the degree that the yoke plug comes into abutting contact with the support yoke.
Subsequently, the yoke plug is loosened until the clearance reaches a target clearance.
However, this method for adjusting the clearance raises the following concerns. Although the clearance is preferably adjusted using, as a reference, a zero clearance position that is the position where the yoke plug just comes into abutting contact with the support yoke, whether the yoke plug is located at a true zero clearance position is not known. Furthermore, when the yoke plug is temporarily fastened, the zero clearance position may vary among products. The variation in zero clearance position may lead to a variation in adjusted clearance.